One pointedness or since minded concentration is the most important ingredient in attaining the tranquility of mind through meditation. In fact, it is your road to the pinnacle of meditation. Imagine throwing a rock in a river; there may be ripples, there may be fishes, but the rock goes pointedly towards the bottom. Think on an arrow from the archer’s bow, it goes straight. There are no diversions. This is one pointed concentration. It is the art of staying on the object of meditation with focus and lucidity.
Maintaining one pointed concentration is a tiring act. It starts to get exhausting after the first thirty minutes. One pointed concentration, is referred to as the ability to hold onto a thought or visualisation. You don’t have to examine the thought or the focus object. You simply have to retain it in front of you. The same principle applies even when you are just watching your breath. You need to concentrate on the inhalation and exhalation.
It takes great practice and in building this concentration you have to go through many stages of mental stillness. One pointed concentration is a definitive way of exponentially increasing the power of your thought. Once you train yourself to concentrate on a thought, your thoughts start to manifest in your life.
Reference : Om Swami. A Million Thoughts.